Embryology

Question 1

Where is the egg fertilized

Answer 1

The ampulla of the fallopian tube

Question 2

What is considered the first fate decision for cells in the blastocyst formation

And when does it take place

Answer 2

ICM cells that will become the embryo or Trophoblast (outside cells that will form part of the placenta)

Begins with the compaction of blastomeres at the 8 cell stage

Question 3

What is considered the 2nd fate steps for the developing embryo

Answer 3

ICM cells either becoming the epiblast or hypoblast

Question 4

What is the epiblast going to become

Answer 4

Amnion and body of the embryo

Question 5

What is the fate of the hypoblast

Answer 5

It will form the wall of the primitive and secondary yolk sacs

Question 6

When does the primitive streak form, where does it form, and what is the significance of this

Answer 6

Early in the 3 week, begins in the caudal half of the disc. Epiblast cells migrate laterally and anteriorly through the primitively streak

Question 7

What are the 3 germ layers

Answer 7

Ectoderm
Mesoderm
Endoderm

Question 8

What is the primitive node/notochord

Answer 8

The primitively node is the anterior end of the primitively streak and the notochord is mesodermal cells forming a solid chord in the midline

Question 9

What will the notochord become

Answer 9

It will become the nucleus pulposus of the vertebral discs as well as induce ectoderm to become nervous tissue

Question 10

Sacrococcygeal teratoma

Answer 10

Remnant of the primitive streak that is a benign tumor containing tissues of all 3 germ layers

Question 11

What is is the oral pharyngeal membrane and what does it consist of

Answer 11

Future side of the oral cavity and only ectoderm and endoderm

Question 12

Prechordal plate contributes to what

Answer 12

Forebrain and the oral cavity

Question 13

What is the cloacal membrane

Answer 13

Site of the future anus and is only the ectoderm and endoderm

Question 14

What does the ectoderm become

Answer 14

Nervous tissue (CNS/PNS)
Neural crest cells(ganglia,adrenal medial, melanocytes)
Skin(from surface ectoderm, glands)

Question 15

When is the neural plate formed and what does it do.

Answer 15

It is the ecotoderm above the notochord forming the neural ectoderm. Periphery cells fold the neural ectoderm into a tube. Surface ectoderm covers the neural tube and becomes the epidermis

Question 16

When does the neruo tube close

Answer 16

4 weeks (28) days

Question 17

Neural tube defects

Preventative measures

Answer 17

Failure to close the neural tube at the cranial end causes ancephally
Failure to close the neural tube from the caudal end causes spina bifida

Folic acid

Question 18

What do the neural crest cells become

Answer 18

Ganglion of all types

Question 19

What layers forms the somites

Answer 19

Mesoderm

Question 20

What does the paraxial mesoderm become

Answer 20

Somites and axial skeleton, associated muscle, and the dermis of the skin

Question 21

What do cells front he somites form

Answer 21

The dermis, muscle, and tendons, cartilage, and bone

Question 22

What does the intermediate mesoderm form

Answer 22

Urogenital structures

Question 23

Where do germ cells arise and where do they migrate to

Answer 23

From the epiblast and migrate to genital ridge

Question 24

Lateral plate mesoderm somatic and visceral layer fates

Answer 24

Somatic=body wall, bones and CT

Visceral=cover organs

Question 25

What composes the body wall when the embryonic disc folds laterally

Answer 25

Parietal mesoderm and ectoderm

Question 26

What forms the gut wall when he embryonic disc folds laterally

Answer 26

Endoderm and the visceral mesoderm

Question 27

Where do blood islands first form

Answer 27

In the mesoderm of the wall of the yolk sac

Question 28

Vasculogenesis

Answer 28

Blood vessels derived from blood islands

Question 29

Angiogenesis

Answer 29

Sprouting of vessels from existing vessels

Question 30

Where does the heart sprout from

Answer 30

The mesoderm of the cardiogenic area. And as the neural tube grows/folding of the cranial region, the heart is directed to the thoracic region

Question 31

What does the endoderm differentiate into

Answer 31

Epithelial lining of the GI, lung, thyroid, liver, pancreas

Question 32

When does the fetal period begin

Answer 32

The 3rd month